如果已知Firestore记录的路径，最好的检查方法是什么? [英] What's the best way to check if a Firestore record exists if its path is known?

问题描述

考虑到给定的Firestore路径，最简单，最优雅的方法是检查该记录是否存在，而不是创建可观察和订阅的文档?

Given a given Firestore path what's the easiest and most elegant way to check if that record exists or not short of creating a document observable and subscribing to it?

推荐答案

看看此处

Taking a look at this question it looks like .exists can still be used just like with the standard Firebase database. Additionally, you can find some more people talking about this issue on github here

文档状态

新示例

var docRef = db.collection("cities").doc("SF");

docRef.get().then(function(doc) {
    if (doc.exists) {
        console.log("Document data:", doc.data());
    } else {
        // doc.data() will be undefined in this case
        console.log("No such document!");
    }
}).catch(function(error) {
    console.log("Error getting document:", error);
});

旧示例

var cityRef = db.collection('cities').doc('SF');

var getDoc = cityRef.get()
    .then(doc => {
        if (!doc.exists) {
            console.log('No such document!');
        } else {
            console.log('Document data:', doc.data());
        }
    })
    .catch(err => {
        console.log('Error getting document', err);
    });

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